This invention relates to tenter clips, and more particularly, to tenter clips having a gripper element and a base element which are held together by screw means and held in proper alignment one with the other by means of pintles which also connect the base element to adjacent links of a tenter chain.
A tenter chain runs around sprockets located at a considerable distance from one another on the frame of a tentering machine. Between the sprockets, the chain travels along an extended rail. There are two sets of rails, sprockets, and chains on each tenter frame. The material being processed on said tenter is gripped along its opposite edges by the tenter clip gates and it is gradually stretched sidewise as the rails diverge towards the discharge end. It is highly important that the gates, as a whole, be maintained in substantial alignment as they move the material in order that their pull on the material shall be as nearly uniform as possible. To this end, the tenter clips of the prior art have been provided with surfaces for engaging the rails of the tenter frame. These include one surface or face for riding along the outside surface of the tenter rail and another surface for riding along the top of the tenter rail.
Tenter clips commonly include a base element and a gripper element, and the surface for riding along the outside of the tenter rails normally is on the base element whereas the surface for riding along the top of the tenter rail is usually on the bottom of the gripper element. In order to maintain proper alignment or orientation of the gates, it is important that the gripper element be maintained in proper alignment with the base element.
Tenter clips manufactured by the Marshall & Williams Corporation, of Providence, Rhode Island, have maintained this alignment in the past by providing the gripper element with a downwardly extending surface which contacts a portion of the rail engaging face. This downward extending surface also contains the surface that rides along the rail of the tenter frame. Thus, this downwardly extending surface, which engages the rail contacting face of the tenter clip base element, is held in alignment by means of a screw or bolt which holds the base element and the gripper element together, and on new chains this works very well. However, during use of the chain the bottom surface of this extension rides along the top of the guide rail of the tenter frame. This results in considerable wear on this surface and after relatively short usage this surface is eroded to the extent that it no longer maintains the gripping element in proper alignment with the base element. When this happens, the gripping element must be replaced at considerable cost. Tenter clips of the prior art are shown in FIGS. 2 and 3 of the drawings and will be described in more detail in describing said drawings.
Tenter clips and tenter clip chains are shown in more detail in U.S. Pat. No. 2,178,892 which issued on Nov. 7, 1939 to H. A. MacKnight; U.S. Pat. No. 3,058,191 which issued on Oct. 16, 1962 to J. C. Nash; and U.S. Pat. No. 3,199,165 which issued on Aug. 10, 1965 to F. Hyatt.